1:45 PM - 2:05 PM
[PEM11-16] Energetic particle impact on the Na layer
Keywords:Na layer, energetic particle precipitation, auroral activity
In this presentation, we will introduce our recent investigation, which focuses on energetic particle impact on the Na layer. There are several previous studies on this issue. Of interest is that the previous studies reported conflicting results and/or suggestions in the response of Na density to auroral activity. In some cases the Na density increased, and in others it decreased. Thus, the Na density response to auroral activity is still unclear. We have been working on this issue using ground-based observations, such as Na resonance scattering lidar and European incoherent scatter (EISCAT) radar, as well as Na dayglow measurements from space, such as Optical Spectrograph and InfraRed Imager System (OSIRIS) onboard the Odin satellite. As the results of our investigation, we conclude that the basic auroral effect to the Na density is a decrease not an increase and the decrease is probably induced through Na ion chemistry triggered by ionization due to energetic particle precipitation related with the auroral activity.